US 5,174,598 AGranted

Active suspension system

AssigneeNissan Motor Co., Ltd.

InventorsMasaharu Sato, Naoto Fukushima, Yosuke Akatsu, Itaru Fujimura, Kensuke Fukuyama

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Abstract

An active suspension system for an automotive vehicle is arranged to regulate the attitude of a vehicle body in a flat or balanced state by controlling hydraulic cylinders respectively disposed between a vehicle body and a road wheel, in response to an attitude change of the vehicle body. The active suspension system comprises electromagnetically operated variable vibration attenuation valves, each of which is fluidly connected with each hydraulic cylinder and is followed by an accumulator. Each variable vibration attenuation valve is adapted to be variable in its attenuation constant in response to a vertical acceleration experienced by the road wheel. The variable vibration attenuation valve takes on a low attenuation constant to maintain a high riding quality of the vehicle under a normal cruising condition, and a high attenuation constant to suppress the response of the road wheel under a rough road cruising condition.

Claims10

Dependent claims

An active suspension system for a vehicle having a vehicle body side member and a road wheel side member, said suspension system, comprising:

a fluid-operated cylinder disposed between and connecting the vehicle body side member and the road wheel side member;
a control valve, for controlling an operating fluid to be supplied to said fluid-operated cylinder in accordance with a first command value;
means for detecting a change in attitude of the body of the vehicle and generating an attitude change detection value representative of said attitude change;
means for calculating said first command value in accordance with said attitude change detection value;
means for detecting a vertical acceleration of a movable member functionally connected to said fluid-operated cylinder and for generating a vertical acceleration detection value representative of said vertical acceleration, said movable member being vertically movable during cruising of the vehicle;
means for changing a damping force of said fluid-operated cylinder in accordance with a second command value;
and
means for calculating said second command value in accordance with said vertical acceleration detection value.

5 more elements

Dependencies are inferred from the claim text.